D112. Weight Is More Important Than Age in the Determination of Skull Thickness

PURPOSE: Pediatric craniofacial procedures frequently depend on the thickness of bone, with many procedures scheduled according to patient age. Sex, weight, and adjusted age (for prematurity) have also been hypothesized to affect the thickness of the skull. Herein we investigated the relative effects of age, weight, and sex on pediatric skull thickness. METHODS: High-resolution computed tomography (CT) scans were obtained for 40 healthy children between the ages of 1 month to 5 years. Each skull was delineated along suture lines into occipital, right parietal, left parietal, right frontal, and left frontal bone segments. For each patient, average calvarial thickness was obtained per bone segment and overall per skull. Gamma regression models were created to isolate the effects of age, sex, and weight on bone thickness. RESULTS: Mean patient age was 9.38 (±12.30) months and mean weight was 8.09 (±3.39) kg. Across all five bone segments, calvarial thickness was significantly predicted by weight in kilograms (Std Estimate=1.06, 95% CI [1.04 1.08], p<0.001). Age was a significant predictor of occipital (1.00 [1.00-1.01], p=0.01) and left parietal bone (1.00 [1.00-1.01], p=0.005) thickness, but regression coefficients were still less than those of weight (1.03 [1.01-1.06], p<0.017 and 1.06 [1.05-1.08], p<0.001, respectively). CONCLUSION: Patient weight is a stronger predictor of overall calvarial thickness than age or sex during the first five years of life. Patient weight should be taken into account when planning surgical intervention, especially for calvarial surgeries such as endoscopy-assisted craniectomy that are targeted based on skull thickness.